InDetJetFitterVxFinder.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
/***************************************************************************
                          InDetJetFitterVxFinder.cxx  -  Description
                             -------------------
 
    begin : March 2007
    authors: Giacinto Piacquadio (University of Freiburg),
             Christian Weiser (University of Freiburg)
    email : nicola.giacinto.piacquadio@cern.ch,
            christian.weiser@cern.ch
    changes: new!
 
  2007 (c) Atlas Detector Software
 
  Look at the header file for more information.
     
 ***************************************************************************/
 
#include "InDetSecVxFinderTool/InDetJetFitterVxFinder.h"
#include "VxJetVertex/VxJetCandidate.h"
#include "VxJetVertex/PairOfVxVertexOnJetAxis.h"
#include "VxJetVertex/VxVertexOnJetAxis.h"
#include "VxJetVertex/VxClusteringTable.h"
#include "TrkJetVxFitter/JetFitterHelper.h"
#include "TrkJetVxFitter/JetFitterInitializationHelper.h"
#include "TrkJetVxFitter/JetFitterRoutines.h"
#include "VxSecVertex/VxSecVertexInfo.h"
#include <TMath.h>
#include "TrkEventPrimitives/FitQuality.h"
#include "VxVertex/VxTrackAtVertex.h"
#include "TrkTrack/Track.h"
#include "TrkTrack/LinkToTrack.h"
#include "TrkParticleBase/LinkToTrackParticleBase.h"
#include "TrkToolInterfaces/ITrackSelectorTool.h"
 
 
namespace InDet
{
 
  struct TrackParticle_pair
  {
    double first;
    const Trk::TrackParticleBase* second;
    TrackParticle_pair(double p1, const Trk::TrackParticleBase* p2)
      : first (p1), second (p2) {}
    bool operator< (const TrackParticle_pair& other) const
    { return first > other.first; }
  };
 
  struct Track_pair
  {
    double first;
    const Trk::Track* second;
    Track_pair(double p1, const Trk::Track* p2)
      : first (p1), second (p2) {}
    bool operator< (const Track_pair& other) const
    { return first > other.first; }
  };  
 
  InDetJetFitterVxFinder::InDetJetFitterVxFinder(const std::string& t, const std::string& n, const IInterface*  p) :
          AthAlgTool(t,n,p)
  { 
    declareInterface< ISecVertexInJetFinder >(this) ;
  }
  
 
  InDetJetFitterVxFinder::~InDetJetFitterVxFinder() = default;
  
 
  StatusCode InDetJetFitterVxFinder::initialize() {
 
    //retrieving the udator itself   
    ATH_CHECK( m_helper.retrieve() );
    ATH_CHECK( m_initializationHelper.retrieve() );
    ATH_CHECK( m_routines.retrieve() );
    ATH_CHECK( m_trkFilter.retrieve() );
 
    return StatusCode::SUCCESS;
  }
  
 
  const Trk::VxSecVertexInfo* InDetJetFitterVxFinder::findSecVertex(const Trk::RecVertex & primaryVertex,
                                  const TLorentzVector & jetMomentum,
                                  const std::vector<const Trk::TrackParticleBase*> & myTracks) const {
    Amg::Vector3D myDirection(jetMomentum.Vect().X(),jetMomentum.Vect().Y(),jetMomentum.Vect().Z());
 
    std::vector<TrackParticle_pair> tracks;
 
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracksBegin=myTracks.begin();
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracksEnd=myTracks.end();
    for (std::vector<const Trk::TrackParticleBase*>::const_iterator tracksIter=tracksBegin;
     tracksIter!=tracksEnd;++tracksIter) {
      if (m_trkFilter->decision(**tracksIter,&primaryVertex)) {
    tracks.emplace_back((*tracksIter)->perigee()->momentum().perp(),*tracksIter);
      }
    }
 
    std::vector<std::vector<const Trk::TrackParticleBase*> > bunchesOfTracks;
    
    std::sort(tracks.begin(),tracks.end());
 
    std::vector<const Trk::TrackParticleBase*> tracksToAdd;
    
    std::vector<TrackParticle_pair>::const_iterator tracks2Begin=tracks.begin();
    std::vector<TrackParticle_pair>::const_iterator tracks2End=tracks.end();
    for (std::vector<TrackParticle_pair>::const_iterator tracks2Iter=tracks2Begin;
     tracks2Iter!=tracks2End;++tracks2Iter) {
        if (msgLvl(MSG::VERBOSE)) msg() << " track: " << (*tracks2Iter).first << " and : " <<  (*tracks2Iter).second << endmsg;
      
      tracksToAdd.push_back((*tracks2Iter).second);
      if (tracksToAdd.size() % m_maxTracksToFitAtOnce == 0) {
        if (msgLvl(MSG::VERBOSE)) msg() << " new bunch " << endmsg;
    bunchesOfTracks.push_back(tracksToAdd);
    tracksToAdd.clear();
      }
    }
 
    bunchesOfTracks.push_back(std::move(tracksToAdd));
 
    std::vector<std::vector<const Trk::TrackParticleBase*> >::const_iterator BunchesBegin=bunchesOfTracks.begin();
    std::vector<std::vector<const Trk::TrackParticleBase*> >::const_iterator BunchesEnd=bunchesOfTracks.end();
 
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracksToAddBegin;
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracksToAddEnd;
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracksToAddIter;
 
 
    std::unique_ptr<Trk::VxJetCandidate> myJetCandidate;
 
    for (std::vector<std::vector<const Trk::TrackParticleBase*> >::const_iterator BunchesIter=BunchesBegin;
     BunchesIter!=BunchesEnd;++BunchesIter) {
      
      if (BunchesIter==BunchesBegin) {
        if (msgLvl(MSG::VERBOSE)) msg() <<  " initial fit with  " << (*BunchesIter).size() << " tracks " << endmsg;
    myJetCandidate.reset(m_initializationHelper->initializeJetCandidate(*BunchesIter,&primaryVertex,&myDirection));
    m_routines->initializeToMinDistancesToJetAxis(myJetCandidate.get());
    doTheFit(myJetCandidate.get());
      } else if (myJetCandidate){
        if (msgLvl(MSG::VERBOSE)) msg() << " other fit with " << (*BunchesIter).size() << " tracks " << endmsg;
    std::vector<Trk::VxVertexOnJetAxis*> setOfVertices=myJetCandidate->getVerticesOnJetAxis();
    std::vector<Trk::VxTrackAtVertex*>* setOfTracks=myJetCandidate->vxTrackAtVertex();
    tracksToAddBegin=(*BunchesIter).begin();
    tracksToAddEnd=(*BunchesIter).end();
    for (tracksToAddIter=tracksToAddBegin;tracksToAddIter!=tracksToAddEnd;++tracksToAddIter) {
      std::vector<Trk::VxTrackAtVertex*> temp_vector_tracksAtVertex;
      ElementLink<Trk::TrackParticleBaseCollection> link;
      link.setElement(*tracksToAddIter);
      Trk::LinkToTrackParticleBase * linkTT = new Trk::LinkToTrackParticleBase(link);
      Trk::VxTrackAtVertex* newVxTrack=new Trk::VxTrackAtVertex(linkTT);
      temp_vector_tracksAtVertex.push_back(newVxTrack);
      setOfTracks->push_back(std::move(newVxTrack));
      setOfVertices.push_back(new Trk::VxVertexOnJetAxis(temp_vector_tracksAtVertex));
    }
        if (msgLvl(MSG::VERBOSE)) msg() << " new overall number of tracks to fit : " << setOfVertices.size() << endmsg;
    myJetCandidate->setVerticesOnJetAxis(setOfVertices);
    Trk::JetFitterInitializationHelper::updateTrackNumbering(myJetCandidate.get());
    doTheFit(myJetCandidate.get());
      }
    }
    
    std::vector<Trk::VxCandidate*> myCandidates;
    myCandidates.push_back(myJetCandidate.get());
    //this function has no useful output?
    return nullptr;
    
  }
 
  const Trk::VxSecVertexInfo* InDetJetFitterVxFinder::findSecVertex(const Trk::RecVertex & primaryVertex,
                                                                    const TLorentzVector & jetMomentum,
                                                                    const std::vector<const Trk::TrackParticleBase*> & firstInputTracks,
                                                                    const std::vector<const Trk::TrackParticleBase*> & secondInputTracks,
                                                                    const Amg::Vector3D & vtxSeedDirection) const 
  {
 
    Amg::Vector3D myDirection(jetMomentum.Vect().X(),jetMomentum.Vect().Y(),jetMomentum.Vect().Z());
 
    std::vector<std::vector<const Trk::TrackParticleBase*> > bunchesOfTracks;
    
    std::vector<const Trk::TrackParticleBase*> tracksToAdd;
    
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracks2Begin=firstInputTracks.begin();
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracks2End=firstInputTracks.end();
    for (std::vector<const Trk::TrackParticleBase*>::const_iterator tracks2Iter=tracks2Begin;
     tracks2Iter!=tracks2End;++tracks2Iter) {
      if (msgLvl(MSG::VERBOSE)) msg() << " adding track to fit " << endmsg;
      tracksToAdd.push_back(*tracks2Iter);
    }
    
    bunchesOfTracks.push_back(tracksToAdd);
    tracksToAdd.clear();
  
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracks3Begin=secondInputTracks.begin();
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracks3End=secondInputTracks.end();
    for (std::vector<const Trk::TrackParticleBase*>::const_iterator tracks3Iter=tracks3Begin;
     tracks3Iter!=tracks3End;++tracks3Iter) {
      if (msgLvl(MSG::VERBOSE)) msg() << " adding track to fit " << endmsg;
      tracksToAdd.push_back(*tracks3Iter);
    }
 
    if (!tracksToAdd.empty()) 
    {
      bunchesOfTracks.push_back(tracksToAdd);
    }
    tracksToAdd.clear();
    
 
    //now it just uses these bunches...
    //now I have just to make sure that no clustering is done at first iteration
    //while it needs to be done at second iteration (there will be only two iterations)
 
 
    std::vector<std::vector<const Trk::TrackParticleBase*> >::const_iterator BunchesBegin=bunchesOfTracks.begin();
    std::vector<std::vector<const Trk::TrackParticleBase*> >::const_iterator BunchesEnd=bunchesOfTracks.end();
 
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracksToAddBegin;
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracksToAddEnd;
    std::vector<const Trk::TrackParticleBase*>::const_iterator tracksToAddIter;
 
 
    std::unique_ptr<Trk::VxJetCandidate> myJetCandidate;
 
    for (std::vector<std::vector<const Trk::TrackParticleBase*> >::const_iterator BunchesIter=BunchesBegin;
     BunchesIter!=BunchesEnd;++BunchesIter) {
      
      if (BunchesIter==BunchesBegin) {
        if (msgLvl(MSG::VERBOSE)) msg() << " initial fit with  " << (*BunchesIter).size() << " tracks " << endmsg;
    myJetCandidate.reset(m_initializationHelper->initializeJetCandidate(*BunchesIter,&primaryVertex,&myDirection,&vtxSeedDirection));
    m_routines->initializeToMinDistancesToJetAxis(myJetCandidate.get());
        if (!(*BunchesIter).empty()) 
        {
          doTheFit(myJetCandidate.get(),true); //will not delete myJetCandidate
        }
      } else if (myJetCandidate){
        if (msgLvl(MSG::VERBOSE)) msg() <<  " other fit with " << (*BunchesIter).size() << " tracks " << endmsg;
    std::vector<Trk::VxVertexOnJetAxis*> setOfVertices=myJetCandidate->getVerticesOnJetAxis();
    std::vector<Trk::VxTrackAtVertex*>* setOfTracks=myJetCandidate->vxTrackAtVertex();
    tracksToAddBegin=(*BunchesIter).begin();
    tracksToAddEnd=(*BunchesIter).end();
    for (tracksToAddIter=tracksToAddBegin;tracksToAddIter!=tracksToAddEnd;++tracksToAddIter) {
      std::vector<Trk::VxTrackAtVertex*> temp_vector_tracksAtVertex;
      ElementLink<Trk::TrackParticleBaseCollection> link;
      link.setElement(*tracksToAddIter);
      Trk::LinkToTrackParticleBase * linkTT = new Trk::LinkToTrackParticleBase(link);
      Trk::VxTrackAtVertex* newVxTrack=new Trk::VxTrackAtVertex(linkTT);
      temp_vector_tracksAtVertex.push_back(newVxTrack);
      setOfTracks->push_back(newVxTrack);
      setOfVertices.push_back(new Trk::VxVertexOnJetAxis(std::move(temp_vector_tracksAtVertex)));
    }
        if (msgLvl(MSG::VERBOSE)) msg() << " new overall number of tracks to fit : " << setOfVertices.size() << endmsg;
    myJetCandidate->setVerticesOnJetAxis(setOfVertices);
    Trk::JetFitterInitializationHelper::updateTrackNumbering(myJetCandidate.get());
    m_routines->initializeToMinDistancesToJetAxis(myJetCandidate.get());
    doTheFit(myJetCandidate.get());
      }
    }
    
    std::vector<Trk::VxCandidate*> myCandidates;
    myCandidates.push_back(myJetCandidate.release());//pass ownership to myCandidates
    //this function, finally, has no useful output?
    return nullptr;
    
  }
 
  void InDetJetFitterVxFinder::doTheFit(Trk::VxJetCandidate* myJetCandidate,
                                        bool performClustering) const {
 
    
    int numClusteringLoops=0;
    bool noMoreVerticesToCluster(false);
 
    do {//reguards clustering
 
      if (msgLvl(MSG::VERBOSE)) msg() << "InDetJetFitterVxFinder:      ------>>>>         new cycle of fit" << endmsg;
 
      int numLoops=0;
      bool noMoreTracksToDelete(false);
      do {//reguards eliminating incompatible tracks...
    
    m_routines->performTheFit(myJetCandidate,10,false,30,0.001);
    
    const std::vector<Trk::VxVertexOnJetAxis*> & vertices=myJetCandidate->getVerticesOnJetAxis();
    
    std::vector<Trk::VxVertexOnJetAxis*>::const_iterator verticesBegin=vertices.begin();
    std::vector<Trk::VxVertexOnJetAxis*>::const_iterator verticesEnd=vertices.end();
    
    
    //delete incompatible tracks...
    float max_prob(1.);
    Trk::VxVertexOnJetAxis* worseVertex(nullptr);
    for (std::vector<Trk::VxVertexOnJetAxis*>::const_iterator verticesIter=verticesBegin;
         verticesIter!=verticesEnd;++verticesIter) {
      if (*verticesIter==nullptr) {
        if (msgLvl(MSG::WARNING)) msg() <<  "One vertex is empy. Problem when trying to delete incompatible vertices. No further vertices deleted." << endmsg;
      } else {
        const Trk::FitQuality & fitQuality=(*verticesIter)->fitQuality();
        if (TMath::Prob(fitQuality.chiSquared(),(int)std::floor(fitQuality.numberDoF()+0.5))<max_prob) {
          max_prob=TMath::Prob(fitQuality.chiSquared(),(int)std::floor(fitQuality.numberDoF()+0.5));
          worseVertex=*verticesIter;
        }
      }
    }
    if ((max_prob<m_vertexProbCut) && worseVertex) {
      if (msgLvl(MSG::DEBUG)) msg() << "Deleted vertex " << worseVertex->getNumVertex() << " with probability " << max_prob << endmsg;
      if (worseVertex==myJetCandidate->getPrimaryVertex()) {
            if (msgLvl(MSG::INFO)) msg() << " The most incompatible vertex is the primary vertex. Please check..." << endmsg;
      }
 
      m_routines->deleteVertexFromJetCandidate(worseVertex,myJetCandidate);
 
    } else {
      noMoreTracksToDelete=true;
      if (msgLvl(MSG::VERBOSE)) msg() << "No tracks to delete: maximum probability is " << max_prob << endmsg;
    }
    
    numLoops+=1;
      } while (numLoops<m_maxNumDeleteIterations&&!(noMoreTracksToDelete));
      
      if (!performClustering) break;
 
      if (!m_useFastClustering) {
    m_routines->fillTableWithFullProbOfMerging(myJetCandidate,5,false,10,0.01);
      } else {
    m_routines->fillTableWithFastProbOfMerging(myJetCandidate);
      }
      const Trk::VxClusteringTable* clusteringTablePtr(myJetCandidate->getClusteringTable());
 
 
      
 
      if (clusteringTablePtr==nullptr) {
    if (msgLvl(MSG::WARNING)) msg() <<  " No Clustering Table while it should have been calculated... no more clustering performed during vertexing " << endmsg;
    noMoreVerticesToCluster=true;
      } else {
 
    if (msgLvl(MSG::VERBOSE)) msg() << " clustering table is " << *clusteringTablePtr << endmsg;
 
    //now iterate over the full map and decide wether you want to do the clustering OR not...
    float probVertex(0.);
    Trk::PairOfVxVertexOnJetAxis pairOfVxVertexOnJetAxis=clusteringTablePtr->getMostCompatibleVertices(probVertex);
    //a PairOfVxVertexOnJetAxis is a std::pair<VxVertexOnJetAxis*,VxVertexOnJetAxis*>
    
    if (probVertex>0.&&probVertex>m_vertexClusteringProbabilityCut) {
      if (msgLvl(MSG::VERBOSE)) msg() << " merging vtx number " << (*pairOfVxVertexOnJetAxis.first).getNumVertex() << 
        " and " << (*pairOfVxVertexOnJetAxis.second).getNumVertex() << endmsg;
      //      const Trk::VxVertexOnJetAxis & mergedVertex=
      m_helper->mergeVerticesInJetCandidate(*pairOfVxVertexOnJetAxis.first,
                        *pairOfVxVertexOnJetAxis.second,
                        *myJetCandidate);
      //now you need to update the numbering scheme
      Trk::JetFitterInitializationHelper::updateTrackNumbering(myJetCandidate);//maybe this should be moved to a lower level...
 
    } else {
      noMoreVerticesToCluster=true;
    }
      }
      numClusteringLoops+=1;
    } while (numClusteringLoops<m_maxClusteringIterations&&!(noMoreVerticesToCluster));
    
    //now a section should follow where the "complicate" VxJetCandidate is transformed in a conventional "VxCandidate" 
    //so that it can be used also by the normal B-Tagging algorithms...
    //TO BE COMPLETED
    
    //return myJetCandidate;
 
  }
 
 
}//end namespace Rec